Curiosity – coming to Mars – maybe

I took the family to the National Air and Space Museum on the mall. While everyone was gazing at rockets and other bus-sized hardware of glory days past, off in the corner I noticed this, roped off, without a placard even:

But after learning a bit more about how Curiosity will be landed, and watching a video from NASA JPL on the mission sequencing, I was surprised to learn they weren’t using that method, but rather a series of mechanical, dangling drops by wire, and rocket maneuvers, that look more than a bit worrying due to the complex synchronization that must occur. Watch this video:

This artist’s concept animation depicts key events of NASA’s Mars Science Laboratory mission, which will launch in late 2011 and land a rover, Curiosity, on Mars in August 2012.

My view: there’s a lot more that can go wrong. One thruster rocket failure, or a tangled drop wire, is all it would take to doom the mission. Mars is known for eating missions, with an over 50% failure rate, so adding to the complexity during landing, especially that dangling rover under a hovering rocket, looks mighty failure-prone.

It’s basically the same way Phoenix probe has already successfully used for landing – but Phoenix was not mobile so all the balast in empty tanks and no longer useful thrusters did not matter. For a rover it’s better if they are detached for further operation.

You are assuming they actually mean to implement the Curiosity mission. I’ll believe it when I see it. The way things are now, I wouldn’t be surprised if the exhibit were not just an imaginative display, done to soothe starry-eyed visitors and keep the public from realizing just how far they are going to be pulling in their horns, with regard to further space adventures. Or maybe they will do it, but subconsciously want it to fail, and so make awkward plans as you point out — it is hard to tell, with their mental state looking so lame, and their reason for being having been suborned to the latest political cash-cow (“global warming”). Obama is presiding over a third-class mindset of haplessness, social injustice and perennial victimhood of most “folks” (as he calls us, not realizing in his cluelessness that the “f” word begins to resemble the “n” word, with both now meaning “victims”, to those who don’t remember “ask not what your country can do for you; ask what you can do for your country”).

Curiosity is five times the mass of Spirit or Opportunity. Plutonium is heavy. That’s why the airbag thing will not work for this mission. They cannot be scaled up to match the size of curiosity and still fit in the launcher.http://news.cnet.com/8301-19514_3-20013105-239.html

The Great Galactic Ghoul (http://www.authorsabroad.com/uploads/images/GG%20Front%20Cover%20lo%20res.jpg) is generally credited with the loss of so many Mars missions.
I share your concern about the sky crane, especially with no way to test it in a realistic Martian gravity scenario. “Works first time” is not a plan. I wish Curiosity the best, but I’m also glad that Opportunity is still roving and is within weeks of stealing Curiosity’s thunder by finding the first phyllosilicates on Mars, at Endeavour Crater.

Just getting it there in the first place… what’s a little tight- wire act at the end?
But really, the big deal is- just think of all of the carbon pollution from planning- to- launch. We continue to exploit the atmosphere, but think of the poor developing nations which should be receiving the money, instead. Why is NASA still reaching into space? Isn’t their mission to reach out to the developing Muslim world, instead?
How dare they?!
/

Sadly, some folks can’t have a serious discussion of a NASA mission, of ANY type, without dredging up pointless canards like “muslim outreach”.
This program was under development long before the current administration and is scheduled for launch this Fall. I believe it is currently going through launch vehicle integration and testing.
I agree with those who feel the complexity of the launch sequence is worrisome, but as Symon notes this is a much larger vehicle. I’m hoping the engineers dotted their i’s and crossed their t’s.
Re: the sounds in space. Most Americans have no idea how laughable this is, and would probably complain about “no sound!” during most of the video. NASA is trying, I guess, to do a better job of PR to the masses, so “sounds in space” is what we get…

Now that NASA has adopted the metric system, what could go wrong?
“NASA lost a 125 million Mars orbiter because one engineering team used metric units while another used English units for a key spacecraft operation…”
Assessment of NASA’s Use of the Metric Systemhttp://oig.nasa.gov/old/inspections_assessments/g-00-021.pdf
Oh wait…
“NASA criticised for sticking to imperial units”http://www.newscientist.com/article/dn17350-nasa-criticised-for-sticking-to-imperial-units.html

They want to reduce the weight of the rover by jettisoning the rocket assembly. They have traded the complexity of the bouncing balloon for the cable descent. Not sure the cable descent is inherently more complex.

>Sound-effects in space really get under my skin!<
Because 2001: A Space Odyssey was so technically accurate? A movie that showed a moon bus cruising laterally over the surface, rather than making parabolic hops? A movie that showed fill light in the shadows a Discovery out in deep space? A movie that showed the suspended animation beds in the accelerated living area, rather than the free-fall area of the ship, which would wear less on the sleepers?

Leon Brozyna says: July 25, 2011 at 4:49 am
Mr. Murphy will have the final say on this project
///////////////////////////////////////////////////////////////////////////////////////////////////////////
Or, perhaps lady luck!
Seriously, there does appear a lot to go wrong, and if it successfully lands (without damage), that is a monumental achievement in itself that the designers and engineers can rightly be proud of. I wish them all the best.

MSL is indeed ready (although barely). Its cost is a little north $2B. It is the last “BIG” mission that NASA is going to launch for the foreseeable future due to budgetary constraints. There is going to be lots of layoffs at JPL after this because there is nothing else in the pipeline. This had had cost overruns like most NASA missions but when you do one of the kind/first of the kind engineering that is what you get. There is no prototyping and it is very hard to test the equipment in conditions that it will operate, especially with regards to low gravity environment. We do thermal/vac tests as well as vibration tests to see if the spacecraft can survive the outer space and its launch, orbit insertion or landing but things can go wrong.
The metric/British thing was because JPL (which is mandated by NASA and Congress to use metric system) was working with a contractor (Lockheed Martin) that had a DoD heritage British system. Because of this we lost MCO but now the whole thing is rectified.
A few fun facts about the NASA’s capability to track deep-space spacecraft:
We know where a spacecraft is to about +/-10m with respect to its distance to Earth. That is over hundreds of millions of kilometers. We know where the spacecraft IS. Of course this only matters during the cruise for MSL as after it lands we know where Mars is.
The power that the spacecraft has to transmit is typically equal to that of household light bulb (35W to 100W typically). The signal that we receive on the ground is something like 10^-13 (very strong signal) to about 10^-19 Watts. This is after the signal is captured by our 34-m diameter and 70-m diameter antennas at the Deep Space Network. At the high end of that power range we can communicated at about 10 Mbps. That is because we keep our receivers cooled to about 4.7 Kelvins.
We are a victim of our own success. We have so good at doing the near impossible that right now failure is not an option. This has led to cost overruns because we have to bullet proof everything. That is why Mars rovers have lasted close to eight years when they were only planned to operate for only 90 days.
For the record: I am a JPL hack and this is my personal opinion and does not present any position of either NASA or JPL.

Looks like a grand plan. The likelihood of it being built though, let alone launched, is pretty small given the current fiscal problems facing the nation.
Perhaps in 5 to 10 years we can revisit this idea.

they won’t use air-ballons, rather it is lowered down in a controlled fashion. The air bags didn’t work perfectly either in that subsequent testing of that technology had shown that they may rip quite badly. Call it luck 🙂

Bet it will never leave the ground! Besides, how on Earth will they get it there? NASA doesn’t do “space” any more. It probably results from a European Study (I jest) that found that competition was too frightening for some people, & they just couldn’t grasp the vastness of space & the spirirt of adventure & exploration, so much so that it hurt their brains! Therefore, all 27 member states will all make a joint sharing caring group hug multi-cultural contribution on the new space project to Mars, budgetted at 500Bn euros over the next 10 years. 30 years later, at 20 times the original estimate, having wasted billions on test programmes because the chief-scientist said they mustn’t interpret the results of said tests in case it upset somebody somewhere, & achieved nothing, nothing has been built passed a cardboard model gathering dust in a cupboard somewhere (hey but the computer generated imagery is fantastic), the French are insisting that 30 cases of Chateau Lafite ’73 should be allocated along with 500 kilos of Camembert in the stores section of the spaceship, the Germans are demanding it should be 300 cases of Moselle instead with bratverst, the Italians want to take mixed cases of Frascati & Barollo along with copious amounts of anchovies & parma ham, the Brits are bogged down in the engineering with some brilliant ideas but have run out of money with no manufacturing base with which to finish them off, have thrown in the towel & gone down to the only pub left open to sup on an insipid euro-approved low alcohol ale, & are terrified the thing will end up with French auto-electronics to run the life-support & guidance systems. The Germans are crafting a marvellous space frame & rocket engine system from the finest space steels, but insist that the firing sequences must be written in Gothic-German, the Italians have designed the space suits (by Gucci), which frankly my dears are to die for (they don’t work!) Reminds me of the Euro-fighter! The rest are just peed off at being bystanders with their hands in their pockets trying to find some more cash. Come on you colonials out there, get NASA back into space where they belong, stop worrying about AGW leave that to the lunatics in Disneyland!

The whole point of Skycrane is to be able to land in very rough terrain, to avoid boulders, canyon walls, etc., within the landing elipse. So, instead of landing at an interesting spot it was designed for, such as Mawrth, shown in the animation, or the river delta in Eberswalde crater, they are going to land in a very large, very flat, very windy Gale Crater, where they are mainly going to be able to look at the same global dust as every other mission. A huge waste of capability. Just like the Spirit, sent to land on what was very obviously a lava flow and not lucrustine deposits like it was sent for – fortunately that rover went far further than intended and found some of what we were looking for.

Classic JPL digging for dollars. Honestly, a little competitive spirit is needed, but to throw out a tried and true landing concept so we can throw billions of dollars into a better mouse trap (Rube Goldberg style) is just another waste.
Fact is JPL wants more money than just the low cost of another airbag system.
They aren’t going to get it because this thing will never make it past the Mission Review process which balances cost & risk. I know, having been in on those reviews.
Sadly we paid for the mock up and video.

The air bag approach has it’s own major concerns, even though it has been proven to be a workable design. I’ve not worked those programs but I would guess the main problem with the air-bag approach is that your vehicle must then be designed to survive significantly greater dynamic forces than this design for MSL. When you have to make your vehicle tough, you add weight in the form of structure. Added weight means more power consumption to move robot arms/legs/wheels around. This MSL has no solar panels shown, so they’re likely going with something nuclear. Nuclear is nice in that it is more reliable than Solar (gee where have we heard that before?), but unless you’ve got a full steam-engine reactor, you’re talking about a radioisotope thermoelectric generator. Those worked great for the Voyager and Galileo probes, but they are VERY LOWER POWER output. In a gravity well, when you’re trying to move around, this means you have to save weight any way you can. Basically the design here is to go for a mars rover that will maybe last as long as Voyager has. It might seem higher risk, but the rewards are greater because you’d maybe have a rover on Mars for 10-20 years, instead of 5-6.

I’m just as interested in the SpaceX COTS launches to ISS this year for NASA. 3 are scheduled, 2 more demos, 1 live. In 2012, 3 live.
Interesting that the Falcon Heavy will have 2X the payload lift capacity of a Shuttle. First test launch late 2012.Launch Manifest.

Why all this angst and pessimism? How are we to learn anything if we don’t try?
If the majority attitude of ‘it’s to complex and not yet proven thus it will fail and is a waste of money’ were applied in the early ’90s as Pathfinder was being developed, the ‘safe’ airbag landing method would have been lauded as utter foolishness. I’ll note as one who as followed NASA’s mars program closely for the past 15 to 20 years, the airbag approach is impossible with MSL as Symon noted, and is to this day anything but a ‘safe’ landing method itself. We are VERY blessed to have both MERs survive – research their development.
JPL’s only mars lander failure in the past 35 years or so is as Ian W noted, MPL (Mars Polar Lander) in ’98 which itself was not a result of the the humiliating metric conversion error. Rather, it’s landing computer though it had contacted the surface when in fact the sensors ‘felt’s the jolt of the legs deploying, a failure mode not detected thanks in large part to the prevailing “faster, better, cheaper” development philosophy at the time. For the record that is six for seven, a nearly 86% success rate, with most employing some need for “works the first time” technology, including the first successful mars landing ever with Viking Lander 1.
Stop with the lemming-like nay saying attitude and don’t confuse nay saying with skepticism. Both are foolishness and are an embarrassment to this fine site. Research before you type!

The airbag system was pushed to it’s limits to land Spirit and Opportunity. It would NOT scale up.
The airbag system may have LOOKED simple, but tell that to the people that had to make it work…oh yes those are the people at JPL, the people some of you seem so eager to mock, and call fools.
Yes, Mars eats spacecraft. Do you think this is news to the people that designed this system? Or rather is it their unending, all pervasive nightmare?
Who here thinks that the Apollo missions were simple? Or that they were cheap?
What is being attempted with MSL is an order of magnitude or three bigger and better than anything tried before.
You know what I think?
It’s crazy, it’s brave, and it’s glorious, and I hope with all my heart that it succeeds brilliantly.

Anthony, this is a (slightly modified) previously used approach. The bouncing balloon bags worked so well with Spirit and Opportunity that it is tempting to think that is the only way to go, but that approach was by no means a sure deal either. Agreed, Mars is known as a tough place to do a mission, but I think this approach has been relatively well thought out and has as good a chance for success as other landings.

I disagree completely. Synchronization is actually easy. These electro-mechanical systems are extremely reliable. It should be quite obvious that the bouncy airbag idea is actually much more risky ( bag getting tangled in the vehicle machinery, landing in an uncontrolled way and hitting a bad spot, excessive g forces on equipment and structures ) . The only advantage of the bouncy airbag idea is that it is very inexpensive to implement – a beautiful idea for cheaply deploying small and extremely robust gear.

>>My view: there’s a lot more that can go wrong.
Agreed.
I fail to see how all that parachutery, in an almost airless atmosphere, can weigh less than taking more fuel for the retro-rockets. I would like to see the weight comparison.
.

Over at space.com there were some videos from the recently completed Atlatis mission. One part showed video from the SRBs with audio. Really cool shots. There were very interesting clunks and lower frequency ringing sounds. All this from the vacuum of space. Clearly, the sounds were conducted through metal. See http://www.space.com/12355-shuttle-launch-glorious.html at about 4 min.
I first watched the Curiosity landing video a few months ago, and yes is seems far too complex and more prone to failure. It also seems silly they don’t have a second launch planned to up the odds of success and cut the cost of the second mission.
If the Curiosity landing is successful, you’ll have back-slapping congratulations. But that’s a big $2.3 billion gamble. If they are successful, they might start taking even bigger risks. We should be spending for exploration and developing space technology. It’s funny sometimes what people do with other people’s money. At least there are no human lives riding on this one.

I should add that NASA is a huge organization, with lots of different teams working on lots of different items, together with outside contractors. No-one who has spent years designing and building a spacecraft is going to do anything that they think will possibly kill their baby. There are risk/cost/spec tradeoffs in any design, but there is a lot of thought that goes into the best way to make the mission a success.
It’s good to be skeptical, but let’s not let James Hansen and his ilk automatically taint our view of all the hard working men and women at NASA who are doing real applied science (i.e., engineering).

The whoosing sounds are part of artist’s imagination, not of the technical specification. It works for many other projects (including about any space movie) so I don’t think they are a real problem here. Anybody who does not like the unrealistic sound effects in the animation (and sure enough none of them are realistic) can just mute the sound.
Regarding the rube-goldberg scheme, yes I agree the mechanism seems to be complicated. But I’m sure people at NASA are not stupid and they discussed many possible solution variants before choosing this. The braking mechanism has already been proven working on the Phoenix probe so it’s not something that hasn’t ever been tested in real conditions – and for the control system it does not really matter whether it zeroes out on zero or any positive height. The main problem is that the rover really needs to get rid of all the balast it doesn’t need to carry along and leaving it above and then throwing away is IMO really the safest way. Even with additional weight for fuel reserves, spare thrusters and the towing mechanism it’s still going to be lighter than the airbag structure, too. Plus the system can visually navigate to a spot that seems to be most suitable for landing pretty much the same way moon landing was done, instead of blind crash landing with airbags.
Regarding the airbags idea, I just think there is a big problem with scaling. A toy car can withstand quite a lot of crashes to a brick wall which destroy a normally-sized car on first attempt at the same relative speed. The requirements on the container and airbag structure stability and toughness don’t raise linearly with scale. And there is still the chance that the airbag structure may get stuck somewhere from which it may not be able to get out or unfold.
Yes, there is a whole lot of things that can go wrong and there is a whole lot of things that went wrong in past missions. Basically each of them was the ‘must work on first attempt’ to some extent too because we don’t have Mars gravity or several kilometers of Mars atmosphere available here on Earth to test everything. That’s the risk of the project. And as the funds are getting limited, the task is not only to find the single safest way of getting the machine there but also doing so within available budget. Personally I believe a lot of technology that’s going to be used in this project was already quite thoroughly tested in real Martian environment during past missions, so there will not be as much of the ‘must work on first attempt’ untested technologies as some may think.

As a number of other commenters have pointed out, getting Curiosity to the surface is not a simple task. Since the lander is much heavier than Spirit or Opportunity the bouncing ball approach would not work.
The Universe Today blog has a very illuminating article on the problems of delivering heavy payloads to the surface of Mars:http://www.universetoday.com/7024/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/
Bottom line :
1. The atmosphere is not thick enough to slow a landing spacecraft sufficiently between the start of entry and landing. Which is what works for landing on Earth.
2. Mars is too big, and it’s gravity is too strong, to rely wholly on rockets. Which we did for landing on the Moon.
As an aside one thing that sometimes annoys me about some of the comments on WUWT is those people who seem to be unable to resist an attempt to make some kind of political point about everything :
“Seems like a long way to fly for muslim outreach.”
What does this article have to do with muslims? I assume this is supposed to be a jab at Obama … are you aware that this mission was conceived and funded during the Bush administration?
Mike.
PS On the other hand I wouldn’t bet on a safe landing. Unless I could get really good odds.

Karmakaze says:
July 25, 2011 at 6:09 am
Funny how you’re interested in Mars missions while there are headlines like this around:
“East coast hammered by the heatwave: Temperature records smashed all over the U.S. but relief is FINALLY in sight”
I guess it’s hard to deny global warming when you’re being roasted.
So? It’s July. Recent article on this same site shows that in North America there have been worse “heat waves” in the middle of the summer, especially in the beginning of the 1930s. Meanwhile, it’s getting very cold in the Southern hemisphere. On average, global temperatures are down. What’s there to “deny”?
The science is settled: CO2 increase doesn’t result in temperature increase, it’s the other way around. Why don’t we hear from you about record harvests, record fish and lobster catches, the greening of Sahara, and other positive effects of CO2 increase?
Screw the headlines.

dwb says:
July 25, 2011 at 7:21 am
> while its landing does the initial pod with the parachute land on all the other equipment? Why not just use a parachute ?
The air is way too thin; impact speed way too high. That’s one reason why US pre-shuttle astronauts landed in the ocean.
My memory is fuzzy, but I think even the bouncing ball landers had a retrorocket fire in the seconds before impact.
While the bouncing ball landers were a clever idea, I imagine they imposed some substantial design problems on the equipment. Imagine a manned landing (even on Moon) done that way, especially if you have some liquid chemicals you wanted to keep unspilled.

The landing rockets will kick up HUGE quantities of dust.
That will kick Murphy into high gear.
Dust migrating into all sorts of areas,onto video lens, circuit boards and bearings, if successful the mission will not last as long as Spirit or Opportunity.
Opportunity has been cruising on Mars for 7 Years…. WOW

Well there is sound in space, you just can’t hear it because sound needs a medium (like air) to travel along in.
The rover’s mass means the airbag system can’t be used, landing anything on Mars that size and up is difficult due to Mars having a thin atmosphere, it would easier if Mars had none or more atmosphere, a lot of people take landing on Mars for granted because of this, and its probably why so many missions fail, even the engineers get it wrong.
Hopefully this time they won’t and in August 2012 we will have a nuclear powered SUV sized robot lab doing science on the red planet.

The whoosing sounds are part of artist’s imagination, not of the technical specification. It works for many other projects (including about any space movie) so I don’t think they are a real problem here.

Gene Roddenberry experimented without spacey noises for the original Star Trek series, but decided people just needed to hear noise as things go by. So they assumed that the space warp drive would make things they go past warp, shake, rattle, and make noise a microphone could pick up.
Personally, I thought those attitude control rockets were way too busy, but I wouldn’t take that thought very seriously.

Funny how you’re interested in Mars missions while there are headlines like this around:
“East coast hammered by the heatwave: Temperature records smashed all over the U.S. but relief is FINALLY in sight”

Agreed that simpler is better.
It may be that they are planning to land in some difficult terrain where the bags would not work, and where they will need some manuverablility to assure a good landing spot. The thrusters appear to be redundant. We have great technology today for maintaining a hover at a position and to recognize terrain autonomously. Check out Hoverfly…you can build your own.
NASA has historically been as much about innovation and new technology as it has been about space exploration. I sure hope the latter will be revived after the next presidential election.

These landings on mars must be less of an apparent risk to the engineers, after studying the previous landings, engineers must have done their homework and are more confident to attempt this type of landing, we’re witnessing the evolution of Martian landings and there will always be a certain amount of trial and error involved.
If gravity on mars is 62% lower than on earth, 100 kg here would equal 38 kg there, it means that on Martian gravity everything will be 62% lighter, wouldn’t that also mean that the lander would need 62% less fuel, fall 62% slower giving the on-board AI a 62% Increase in reaction time and an overall 62% more stabilizability?

As for the airbags, they won’t work for something this big. The problem is as follows:
Mass increases with volume; strength increases with area. The bigger an object gets, the more fragile it becomes because is mass to strength increases. The volume/strength equations for the airbags do not simply work.

I’ve been following this project from the begining, and I have been scratching my head about the landing system too. However, it seems that the sky crane system doesn’t really have them worried as much as the heat shield. Apparently, it’s experimental material and it’s the biggest ever used. Of course, launch of a big two stage rocket isn’t a piece of cake either.

The launch is actually scheduled in the near future (fall), the target terrain as well as the size was driving the choice of landing systems. Also with the time delay in earth mars transmission no direct control is possible so the landing system must be able to handle what happens to be below.

I’ll bet it works. If they can soft land a probe on Saturn’s Titan they can surely do this. Now that the Space Shuttle’s been retired – and the ISS basically off our books (it is isn’t it?), lets go to Europa! I’m serious. Lets take robotic exploration up a notch. Who’s with me?

What a wonderful looking rover! When released from the cargo hold, it will be great for scouting missions before the humans disembark from the lander. (Ah, we can always dream…)
But wait, they are powering it with RTG’s and have brought up the dreaded “P word.” This will automatically invoke esteemed theoretical physicist Michio Kaku popping up on ABC News (US) and elsewhere to remind us, post-Fukushima, that Plutonium is the deadliest most-lethal most-evil substance in existence, one speck too small to see will lodge in your lungs and kill you with lung cancer. Therefore the mission is a perfect example of the scientifically-ignorant supremely-arrogant American government once again not considering the consequences to the global community as a single mishap could wipe out an entire continent, leave it uninhabitable for millions of years, and kill people worldwide for untold millenia due to any radioactive dust that escapes the devastated wasteland.
The UN will then issue a resolution condemning the US for failing to properly consider its obligations to the international community (it’s bad enough the US wrecked the global climate with its carbon emissions) and demanding the mission be stopped. The US will graciously accede to the demands of the global community and scuttle the project, which will be met with relief by many people as China, Iran, and North Korea were prepared to initiate UN-endorsed military action against the US to prevent this act of potential genocide.
Oh well. Maybe before we can explore Mars, to keep the Greens happy we’ll have to set up a recharging station for all-electric battery-powered rovers. Will a 30-meter wind turbine be sufficient? On Earth that’s considered enough to power about 100 homes, even with the thinner Martian atmosphere it should be able to keep one rover powered, right?
☺

The Angry Red Planet is awaiting. Send in the next candidate probe. Mars will let you know what it thinks of the latest contraption.
What is wrong with sending up a dozen or more Spirits & Opportunites? Why is bigger always better?
NASA may have come down with a case of Aperture Fever.

I’m utterly impressed with the folks at JPL and NASA and their capacity to “do”. Sure, some things don’t work, mistakes are made, but look at the things that have. We learn and we move foreword and that is how humanity progresses. Nobody’s done it better. Do you think they purposely designed this mission to fail or be ridiculously stupid? It just doesn’t work like that. Being a Gemini and Apollo kid and NASA contractor for 21 + years, I’m so glad I’m not an armchair whiner because you quivering chins don’t know diddly-squat.

upcountrywater says:
July 25, 2011 at 9:53 amThe landing rockets will kick up HUGE quantities of dust.
I’m assuming that the high wire act is so that the landing rockets are far enough away from the surface that they don’t kick up any dust in the vicinity of the lander.

Anthony, as a former JPLer who worked in operations for many projects, including Spirit and Opportunity, let me summarize most of what has already been said.
Airbags will not scale to the weight of the payload, so a retro-rocket is the way to go. Just like they did with the Vikings, and the Apollo Lunar Modules. Remember, Mars has a fraction of the atmosphere and gravity we’re used to.
The tether system is likely being used for several reasons. Most obvious is to mitigate blown debris from the retros. Since they are using optical sensors to see the landscape and select a safe spot, they can’t have blowing material adding confusion. This lessens the chance of a mistake and having the rover stranded on top of a rock. Additionally, this method lessens the chance of damage to the rover from flying objects and keeps the landing site more pristine.
Inserting a payload in orbit around another planet is hard enough as it is, let alone landing delicate equipment on the surface. Major differences in atmosphere and surface conditions pose a serious challenge. The biggest hurdle is time. Given the distances involved, nothing can be done in anything that resembles real time. OWLT (One way light time) to Mars can range from 4 to 21 minutes, meaning a round trip signal can be nearly an hour delay. Modern missions have been very successful. The failure rate is skewed by a lot of early Soviet failures.
JPL is probably the best part of NASA there ever was. While some deride mission costs in the hundreds of millions, the cost of unmanned projects pale in comparison to the price of a single manned launch. When it comes to science, JPL has Houston beat by miles. Manned space got all the press and outreach, just so the public could watch astronauts eat a spinning banana. JPL could certainly use a budget boost, but then again, NASA’s budget isn’t all that large to begin with, and JPL’s slice was tiny.

@sman67 says:
Hey, thanks for taking the time to explain that! What I didn’t say in my original comment was that I find this mission very exciting, and upon seeing the video a few weeks ago I emailed it to both of my brothers.
JPL has done some of the greatest robotic exploration ever, and if the rest of NASA (I’m looking at YOU MSFC) was on par with the folks who work at JPL, we’d have a moon colony by now.

NoAstronomer says:
July 25, 2011 at 9:22 am
Wrote
As an aside one thing that sometimes annoys me about some of the comments on WUWT is those people who seem to be unable to resist an attempt to make some kind of political point about everything :
“Seems like a long way to fly for muslim outreach.”
What does this article have to do with muslims? I assume this is supposed to be a jab at Obama …
I read Michael D Smith’s comment. I did not see reproach to any particular president.
I just the reproach of the stupid directive that director Charles Bolden said he was givenhttp://blogs.abcnews.com/politicalpunch/2010/07/white-house-nasa-defend-comments-about-nasa-outreach-to-muslim-world-criticized-by-conservatives.html
So, lot of us (like me, who grew up falling in love with astronomy. that is what led me to take engineering as my major. i wanted to come up with a better fuel !! ), are at this point very saddened by the decision to put “muslim outreach” as an important goal, instead of making the science as the single most important goal; or “inspiring future generations into science, space and technology” as important goal.
It is a shame when politcal hacks like you write all this “I assume” garbage. I don’t know where you get off “assume”ing what the other guy is “implying/thinking”?

@Alexander Feht
“So? It’s July.”
Oh, I see… record breaking heat is because it’s summer, record breaking cold is because AGW is a lie, and thousands of scientists are participating in the greatest scientific fraud, ever.
“On average, global temperatures are down.”
Are they?http://wattsupwiththat.com/reference-pages/global-temperature/
I notice the 1998 warming is labelled “El Nino Warming” but the 2007 “cooling” is NOT labelled “La Nina Cooling”. I also notice that the second half of the graph is mostly above the average and the first half below the average.
Now how can you say that temperatures are down when 1983 was colder than 1993 and they were both colder than 2003 or now.
Either you simply can not understand what is being discussed, or you are intentionally ignoring the facts in favour of a political belief.
“The science is settled: CO2 increase doesn’t result in temperature increase, it’s the other way around. ”
Whatever. It’s the sun, cosmic rays, a fraud, an error… anything but AGW… right? The only thing that is settled is your mind. Nothing will ever change it, because you refuse to accept any conclusion that contradicts your own.
“Why don’t we hear from you about record harvests, record fish and lobster catches, the greening of Sahara, and other positive effects of CO2 increase?”
Why don’t hear from you about the empircally PROVEN “greenhouse” effect of CO2 that is REQUIRED by physics? We are not talking about people looking at the sky and saying “CO2 did it” we are talking about lab experiments determining the warming effect of various gas concentrations in the atmosphere. CO2 (and other GHGs) MUST warm the atmosphere. If it didn’t, we wouldn’t exist.
So can you explain to me how CO2 can cause warming in lab experiments, but not in the real world? Try it. It will be amusing to see.
“Screw the headlines.”
Yeah, screw em! Who needs reality when we have a global conspiracy of evil scientists to fight!
@Ric Werme
“Funny how you’re interested in TX/OK/NM weather (and WA/OR/MT I trust) here when it’s well covered”
That article is about a drought, not about a heat wave. But fair enough. Buried in the middle of the article is a small mention of the heat wave affecting the entire US, while he discusses where the drought is centered.
So the words “heat wave” are used exactly ONCE in that article:
“Though the heat wave has spread into the wet areas further north this week creating a literal sauna, the rains and cooling will return there n the next 8 days but the drought will persist in parts of the southern plains.”
Yes, the “heat wave” has been adequately covered on this site, according to it’s authors and fans. Not a mention of the deaths. Just a quick note to say “ah, but it will be gone soon”.
Pfft. Try again.

Bennet Wrote: JPL has done some of the greatest robotic exploration ever, and if the rest of NASA (I’m looking at YOU MSFC) was on par with the folks who work at JPL, we’d have a moon colony by now.
Thank you Bennet. One of the reasons that JPL tends to have a better track record than other NASA centers is that nobody here is a civil servant. We are all employees of Caltech. If the budget is tight or we are no longer useful, we get laid off and more useful people get hired instead of us. That does two things: first, we tend to be leaner and younger here at JPL. Second, we tend to be more technically oriented. At other centers where the civil servants form a large portion of the workforce, they tend to manage the contracts while the for-profit contractors do all the technical work. That way, if a project ends or gets cancelled, the contracting people are let go but not the civil servants since it would be very difficult to let them go. Sean O’Keefe, the only non-Engineer administrator that I have worked for was the only guy to realize this and had a proposal to make all NASA centers work like JPL and have universities take over the workforce but that did not happen. If it had, NASA, IMO, would have been a much better organization. Not that JPL is perfect since we still tend to gold-plate our stuff but we have a lot of technically savvy people around. Of course I shouldn’t generalize as all the people that I have come across at JSC have impressed me as very good managers.
During the past year we have laid off about 300 people at JPL. With no big projects in the works and NASA budget being what it is, we may have to let go of some more people next Fiscal Year.
Again these are all my opinions and do not reflect JPL or NASA policy.

karmakaze says:
“Why don’t hear from you about the empircally PROVEN “greenhouse” effect of CO2…”
There is no ’empirically proven’ greenhouse effect, as R.W. Wood showed by experiment. A greenhouse effect may exist, but there is no testable, empirical evidence of a greenhouse effect, per the scientific method. It is a model-based conjecture which could be true, but your understanding of ’empirically’ is wrong, and in this context so is your misuse of ‘proven.’ If it were proven, there would be no debate over the climate sensitivity number.
This is the internet’s “Best Science” site. It isn’t realclimate or climate progress. Words have specific meanings, and you are misusing “empirically proven”. You probably just don’t understand what the words mean, that’s all. Climate alarmists are no different than Humpty Dumpty: they believe that words mean whatever they want them to mean. That’s why alarmists always get the science wrong.

Actually that is quite an elegant and simple system. Lowering the rover by cable significantly lowers the centre of gravity on the landing system which would be an enormous help with stability, and counteracting any unexpected wind gusts, and also keep the thrusters sufficiently high enough above the surface to avoid issues with dust. I should imagine there is considerable degree of elasticity built into those cables to further help with shock absorption. The quick release system on toutch down means that the landing module doesn’t have to exactly counteract the weight of the rover just slow it down enough to place it on the surface without damage. Basically aim for the sweet spot, but the combination of elasticity in the cable, and instant release on touchdown gives you quite a wide window to fit through.

metryq says (July 25, 2011 at 5:52 am): “Because 2001: A Space Odyssey was so technically accurate?”
While that film predictably traded off accuracy for entertainment, it did show how to keep a silent space sequence interesting: add music. In the first part of the MSL video, I can imagine a little “traveling music” punctuated by musical effects (drum, cymbals, etc) for events such as stage separation. Once in the Martian atmosphere, sound effects are appropriate, but more music wouldn’t hurt.
Presumably it was faster and cheaper to stick with sound effects only. 🙁

As the proverbial rocket scientist (engineer): Spirit and Opportunity were washing machine sized. This is a Jeep. Bouncing bags would pop with this much mass. That’s been seen in testing as reported on Nova, I believe. Parachutes (all the way to the ground) tend to drift into hazards, foul the vehicle, or fail to separate at all. All are likely failures with loss of mission as a result. Rockets are a solution given the mass and conditions. The cable drop is a solution to when to turn off the rockets and how not to be dragging the rockets and tanks around for the rest of the mission. This is complex, but it’s of the complexity needed to safely land a large, mobile probe on Mars.

Re Karmakaze on July 25, 2011 at 2:33 pm:
Heh, silly little warmist troll wants to hijack a space exploration thread to spew his assertions and accusations. By the sheer quantity he must really enjoy that tingle he gets when ranting.
Space exploration was led by those who were critical of what was accepted. By boldly challenging the existing “settled science” humanity made it off this planet. By questioning the unquestionable, someday we shall make it to other stars.
And this little troll wishes to tell us this science was long proven, there is nothing new to be learned, none of it will ever be disproven, can’t be disproven, so we should all just shut up, stop being critical, stop questioning, and just accept what the self-certified Climate Experts™ tell us is the Absolute Unalterable Truth.
Heh. You keep dreaming that’ll happen, little troll. We’ll stay skeptical and keep dreaming of how to reach for the stars. 😉

weasel53 says:
July 25, 2011 at 11:37 am
> I’ll bet it works. If they can soft land a probe on Saturn’s Titan they can surely do this.
There’s a decent atmosphere on Titan (60% greater than Earth!) – parachutes work.
Hmm, Mars’ atmospheric pressure is some 99.3% less than Earth’s.

Okay, so Mars eats ships. So what? Exploration eats ships, it always has. Look around the coastlines of any continent for proof.
If the engineers at JPL think this is the way to do it, then I’m willing to believe they know what they are doing. But win, lose or draw it’s worth the effort.
People like those at JPL are keeping alive the tradition that gave us names like Cook, Da Gama, Drake and Columbus. A tradition that dates back to the first caveman that wondered what was on the other side of the next hill. The curiousity, the desire to “go and see”. Whether by probe or rover or by boots on the ground, it’s the same desire and to lose that is to lose a part of our humanity.
I say “Good luck Curiousity and JPL, and Gods speed”.

@Karmakaze says:
July 25, 2011 at 2:33 pm
Re: all that stuff you wrote (and wrote, and wrote)… so tell me again how all that relates to getting a “Jeep” on Mars? I couldn’t make heads nor tails of your opinion of the topic at hand.
On topic: The lunar landing module worked out OK. I think they have a good shot with this.

sman67 says:
July 25, 2011 at 6:12 am
Thanks for the information. One thing about the crane approach interests me after reading your comment on the power used in relation to the crane approach. I am assuming that the rover has solar panels to recharge the unit. Is there not a problem with the dust raised by the thrusters then coating the panels?
By the way, watching the vid on my laptop at night with the lights out was fun! Quite scary when the bits pop off! Reminded me of the old TV advert in the U.K. with the by line “Take your littler home”!
Hope the thing works well even though I side with Anthony on the “If it can go wrong…it will”!

Binny says:
July 25, 2011 at 4:12 pmActually that is quite an elegant and simple system. Lowering the rover by cable significantly lowers the centre of gravity on the landing system which would be an enormous help with stability…
Actually, quite the opposite. It becomes a growing pendulum. These are tricky to control, particularly by humans, as anyone who has flown loads under a helicopter will be able to tell you.

Remember in the old days when spaceships were named by MEN and WOMEN with guts? Like Apollo, and Viking? Is it just me or is ‘curiosity’ the gheyest name ever for a spacecraft/rover? Who names these things? Why don’t we name it Hope and Flowers?
And another thing – Where does Curiosity fit in with NASA’s new Muslim Outreach Program.

If you’ll take another look: There are actually three cables tethering the lander/rover to its thruster during the final descent phase. This “triangulation” will allow for some counteraction to the pendulum effect, keeping oscillations damped within limits. This sort of triangular damping is not generally available when helicopter-lifting, as that is generally done with single cable or sometimes two-point lifting.
If the whole setup gets to that point – and assuming that the thrusters don’t falter and that the release mechanisms work o.k. – that final phase seems likely to work quite well.

Easy. The moon has no atmosphere and a lot less gravity.
Not necessarily. The lack of atmosphere makes a lunar descent and landing more difficult than on a planet with an atmosphere. There is no atmosphere for aerobraking with heat shields and parachutes. There are ways to adjust an orbit to use gravity for some deceleration, but most braking is by pure rocket muscle power. So you have to bring more fuel along.

“Thanks for the information. One thing about the crane approach interests me after reading your comment on the power used in relation to the crane approach. I am assuming that the rover has solar panels to recharge the unit. Is there not a problem with the dust raised by the thrusters then coating the panels? ”
That’s one reason to suspend the payload far beneath the thrusters. Also, keep in mind that there are windstorms on Mars. At one point either spirit or opportunity were about to croak due to dust on the panels, but a windstorm came along and cleaned the panels, reviving the little booger.
Those rover missions lasted far longer than their design spec. They were also designed and operated by JPL. Real Engineers dealing with real missions. I hope they design us a moon base soon, because a manned mars mission is extremely impractical. A moon base is a practical goal with many tangible benefits to be had. If this nation needs anything, it’s a positive goal to replace this seemingly endless crisis mentality and defensive posture.
Hopefully those bright minds at JPL will be there when we decide to do it. My guess is that in a couple of years, they’ll be hiring again at JPL, and that will be a good day indeed.

>>NoAstronomy
>>2. Mars is too big, and it’s gravity is too strong, to rely wholly on
>>rockets. Which we did for landing on the Moon.
The Russians used to land men on Earth, using just a parachute and retro rockets.
>>Karmakanze
>>Funny how you’re interested in Mars missions while there are
>>headlines like this around:
>>“East coast hammered by the heatwave:
Funny how you are not interested in northern Europe having no summer this year.
.

@Dave Worley
Not necessarily. The lack of atmosphere makes a lunar descent and landing more difficult than on a planet with an atmosphere.
In the case of Mars your are incorrect.
Mars has not enough atmosphere to make it easy in terms of using a chute and aerobraking, (for example this landing is going to be 4.5km below the datum, that is a lot of extra atmosphere there using to help land this beast). You need to use technology that incorporates landing devices for both atmospheric and non atmospheric landing, making Mars more difficult to land on than Earth or the Moon.
On the other hand in orbit around Mars is one of the easiest places to go to and land from Earth which of course is Phobos, (easiest in terms of delta V requirement). A space elevator will be a excellent future option (if technically feasible) for landing on Mars and escaping its gravity well.

But we can put a manned base on the moon. We have the technology to do it very quickly.
There is a common misconception that we would need some solid pressure container or to excavate caves in order to dwell there. Humans can work in a 5 psi environment. Think about that. That’s less pressure than the average fun jump contains. A base can be a lightweight inflatable structure. Furthermore, folks working there can wear a lightweight pressure suit which would deploy in the event of a sudden loss of pressure. Another common misconception is the amount of time that a person can survive in a vacuum. Check it out, you may be surprised.
We should be engaged in a serious plan to make a base in a crater near one of the lunar poles to set up and operate an observational telescope. Those can also be made now with very lightweight materials, focused with peizoelectric actuators. There are also plenty of scientific and industrial benefits to be derived from such a base. All of this is doable if only a few of our aerospace contractors would develop the cajoles to speak up and offer their expertise. I’m sure there are plenty of folks at NASA and JPL who would be very excited to rise up to such a challenge.
About all we have now is that Branson fellow crowing about shooting a little glider up for a 2 minute non orbital amusement ride into “space”. In a national media interview he had the audacity to describe the flight as about 90 minutes long, somehow neglecting to explain that all but a couple minutes is the ride up to launch altitude under the mother ship, and the glide down. No need for a heat shield, it’s not going fast enough. Of course the reporter never bothered to ask how long one would actually be in space.
Everyone is tired of hucksters. We long to do something real, something tangible, and something we can be real proud of doing. We are seriously lacking in positive goals these days.
Anthony, this might be a good next step for you to help promote something very positive, since the whole fear mongering global warming/climate change fad appears to have finally found its place in history with pet rocks and cabbage patch kids. I expect that someone with your influence could help tremendously to get such a bold idea moving.

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